Side wall shoe supporting mechanism for floating tank roofs



United States Patent SIDE WALL SHOE SUPPORTING MECHANISM FOR FLOATINGTANK ROOFS John H. Wiggins, Woodside, Calif.

Application April 18, 1955, Serial No. 501,877

4 Claims. (Cl. 220-26) This application is a continuation in part of mypending application for patent Serial No. 334,006, filed Ianuary 19,1953, now Patent No. 2,754,026.

This invention relates to a novel mechanism for mounting an annular sidewall sealing shoe on a floating tank roof.

One object of my present invention is to provide a novel side wall shoesupporting mechanism whose coacting parts are of such design that themechanism, as an entirety, is compact and small enough to enable it tobe arranged in the space between the side wall shoe and the rim of theroof, and which is of such construction that the shoe remains atpractically the same level as it moves radially, inwardly and outwardly,relatively to the rim of the roof.

Another object is to provide a side wall shoe supporting mechanismcomposed of a plurality of sets or pairs of rock arms mounted on theexterior of the rim of the roof and joined by links to the side wallshoe, each of said sets or pairs comprising two rock arms arranged inradial relationship with each other and constructed in such a mannerthat in all positions of the mechanism, the push or pull of the frontand rear rock arms tends to balance the net outward thrust of the entiremechanism, due to the weight of the shoe.

Figure l of the drawings is a fragmentary, vertical, sectional view of afloating tank roof seal, equipped with a side wall shoe supportingmechanism embodying my invention, said mechanism being shown in sideelevation.

Figure 2 is an elevational view at right angles to Figure 1 with the rimof the roof omitted and showing the inner face of the side wall shoe.

Figure 3 is a top plan view of the shoe supporting mechanism, said viewbeing taken on the line 3-3 in Figure 1, looking in the directionindicated by the arrows, and

Figure 4 is a detail view illustrating how the links 11 are attached tothe side wall shoe.

In the drawings 1 designates the circular side wall of an oil storagetank that is equipped with a floating roof 18 provided at its peripherywith an upwardly projecting annular rim C which is arranged in spacedrelation with the tank side wall. The means that is now generally usedto seal the space between the tank side wall 1 and the rim C of the roofcomprises a circumferentially flexible annular shoe A carried by theroof and arranged in sliding engagement with the tank side wall, and afabric sealing element D of any preferred construction attached in anypreferred manner to the side wall shoe and to the rim of the roof at apoint above the surface B of the liquid on which the roof floats. Mypresent invention consists of a novel supporting mechanism for the sidewall shoe that is capable of being arranged between the side wall shoeand the rim of the roof, at a point above the fabric sealing element D.

Briefly described said shoe supporting mechanism is composed of aplurality of sets or pairs of rock arms 6 and 7 pivotally mounted on theexterior of the rim C 2,790,575 Patented Apr. 30, 1957 of the roof andhaving their upper ends joined by links 11 to the side wall shoe A, thelinks 11 being hinged or pivotally attached to the side wall shoe andprojecting inwardly from same, and the two rock arms 6 and 7 of eachpair or set of rock arms having their upper ends pivotally attached tothe particular link 11 associated with said set or pair of arms. Therock arms 6 and 7 and the links 11 that are associated with said rockarms, are so designed and proportioned that they maintain the side wallshoe at a substantially constant level when said shoe moves radially,inwardly and outwardly, relatively to the roof, as shown in broken linesFigure 1. In the preferred form of my invention herein illustrated thearm 6 of each pair or set of rock arms consists of a relatively long,yoke shaped member arranged in an upright position with the lower endsof its two side portions provided with laterally projecting extensions 6that are rockably mounted in lugs or brackets 52 on the exterior of therim C of the roof and with its closed upper end portion 6 disposedhorizontally so that it will serve as a pivotal connection between saidarm 6 and the intermediate portion of the particular link 11 with whichit is asociated. The arm 7 of each pair or set of rock arms, consists ofa relatively short elbow shaped member whose vertical portion has itslower end pivotally attached by a pivot or pintle pin 51 to laterallyprojecting lugs 50 on the exterior of the rim C and whose angularlydisposed upper end portion is pivotally attached by a pivot pin 55 tothe inner end of the particular link 11 with which said rock arm isassociated. As shown in Figure l, the short arm 7 is mounted on the rimat a higher level than the point where the long arm 6 is mounted, withthe result that the upper ends of the arms 6 and 7 are attached to thelink 11 at about the same elevation. The link 11 that cooperates witheach set or pair of rock arms 6 and 7 is arranged in a substantiallyhorizontal position and is provided at its inner end or right hand endwith a forked or bifurcated portion 11 as shown in Figure 2, thatloosely straddles or embraces the angularly disposed upper end portionof the particular rock arm 7 with which said link is associated, therebymaking it possible for the inner end of the link 11 to move sidevvise orcircumferentially a slight distance, relatively to the rock arm 7. Theouter end or left hand end of the link 11 is hinged or pivotallyattached in any suitable manner to the side wall shoe A, as for exampleby means of a hook 111* on the link that projects into a rectangularhole in a channel shaped member 53 which is secured to the side wallshoe by fastening devices 54.

The long arm 6 of each set or pair of rock arms is disposed in front ofand in radial alignment with the short arm 7 of the set, and said twoarms are so proportioned and arranged that when the side wall shoe is inclose proximity to the tank rim as shown in full lines in Figure 1, saidarms will be in a substantially vertical or upright position and withthe angularly disposed upper end portion of the short arm 7 extendinginwardly over the top edge of the rim on the roof. When the side wallshoe moves outwardly away from the roof rim, the plurality of sets orpairs of rock arms 6 and 7 located around the circumference of the roofrim C, maintain the side wall shoe at nearly the same level said shoeoccupied when it was located in close proximity to the rim, and in allpositions of the mechanism, inwardly and outwardly, the push or pull ofthe front and rear rock arms tends to balance the net outward thrust ofthe entire a i 3 shoe in intimate sliding engagement with the innersurface of the side wall, and a floating roof within the tank having itsperimeterdefinedby an upstanding peripheral rim spaced radially inwardlyof the shoe, means on said roof forsnpporting said shoe so as to permitrelative radial movement between the shoe and the roof while maintainingsaid shoe at reasonably constant level with respect to the roof,comprising a pair of rock arms of different length extending upwardly inthe space between said shoe and said rim of said roof, the respectivelowermost ends of said rock arms being pivotally attached to said rim atdifierent levels below its upper edge, and a radially extending linkpivotally attached to and interconnecting the upper end portions of saidarms and having its outer end pivotally attached to said shoe, said armsand said link serving to uspport said shoe and being adapted to moveradially inwardly and outwardly with respect to said roof to permitcorresponding relative movement of said shoe.

2. The combination set forth in claim 1, wherein the lowermost end ofthe longer one of said arms is pivotally attached to said rim at a levelbelow the lowermost end of the shorter one of said arms.

3. The combination set forth in claim 1, wherein the lowermost end ofthe longer one of said arms is pivotally attached to said rim at a levelbelow the lowermost end of the shorter one of said arms, and wherein theupper end portion of said longer arm is pivotally secured to said linkbetween said shoe and the point of attachment of the shorter of saidarms to said link.

4. The combination set forth in claim 3, wherein said shorter one ofsaid arms is elbow shaped and its upper end portion and the inner end ofsaid link are adapted to overhang said roof when the space between saidshoe and said roof at the location of said link is at a minimum.

References Cited in the file of this patent UNITED STATES PATENTS2,542,444 Wilkin Feb. 20, 1951 2,554,497 Moyer May 29, 1951 2,630,937Orr et al. Mar. 10, 1953 2,685,982 Moyer Aug. 10, 1954

